NINE months after the Governor Mr Chris Patten was challenged to visit Hongkong's second worst temporary housing area, he has gone one better and will visit the territory's worst THA next month. And challenger Mr Cheng Tze-yau, a volunteer with the Hongkong Christian Service, is praying for bad weather. ''I hope June 23 is a rainy day, so he can experience water dripping from roofs and the messy environment,'' said Mr Cheng. Mr Patten promised Mr Cheng during a public roadshow forum last October that he would visit the 15-year old Shun Lee Tsuen to witness first-hand the hardships experienced by the 1,700 residents. But during a visit to the Kwun Tong District next month, the Governor will stop off at the 18-year-old Ping Shek THA instead. Mr Cheng said he hoped Mr Patten would visit Shun Lee Tsuen too. ''It's as bad as Ping Shek,'' he said.